Blast furnace top



United States Patent 2,151,514 3/1939 Heinen 214/35 2,760,771 8/1956Knappe 266/27 3,198,623 8/1965 Evansetal 214 35x Primary Examiner-RobertG. Sheridan Attorney-William G. Young ABSTRACT: A blast furnace topcomprising a hopper that provides a gastight cover for upper end of thefurnace stack. The hopper is a gas tight enclosure and has a downwardlyextending screw conveyor for feeding stock therefrom into the furnace,and a supply chute through which stock is fed thereto from a skip hoist.A pair of valve gates in the chute form a gaslock and operate to controlthe gravitational movement of stock through the chute into the hopperand to prevent the leakage of blast furnace gas therefrom. A pressureequalizing conduit connects the interior of the hopper with the furnaceofftakes to minimize the leakage of blast furnace gas through the screwconveyor into the hopper.

Patented Dec. 1, 1970- Sheet g 013 INVENTOR #442040 F. SHEA/26 BY MATTORNEY Patented Dec. 1, 1970 INVENTOR HARQLD F. SHE/5Z5 ATTORNEY BLASTFURNACE TOP This invention relates to blast furnaces for producing pigiron and, more particularly, toa charging top therefor which, asindicated above, is in the form of an enclosed hopper that forms agastight cover over the upper end of the furnace stack when mountedthereon and has a screw conveyor for feeding stock therefrom into thefurnace.

Blast furnace charging tops at present are equipped with double bellsand hoppers for charging iron ore and other stock materials in thefurnace and for preventing the leakage of gas therefrom, a third belland hopper being frequently employed to provide a more effective sealagainst gas leakage. The bells must be operated in a predeterminedsequence and this results in the stock being fed intermittently to thefurnace. Operation ofthe bells to feed stock to the furnace in thismanner requires a complicated mechanism in the form of-bell beams on thetop platform of the furnace, concentric bell rods on which the bells aresuspended, and bell hangers and cables connecting the bell rods with thebell beams for actuation thereby. The bells and their operatingmechanism are both subject in practice to well-known and troublesomeoperational and maintenance problems.

One of the principal objects of this invention is to provide a chargingtop for blast furnaces which eliminates the bell and hopperconstructions now used in conventional blast furnace tops, and theintermittent stock charging operation that is had in such constructions.A related object is to provide a charging top which operates to feed thestock continuously to the furnace.

A further object of the invention is to provide a blast furnace chargingtop in which all essential parts thereof may be preassembled as a unitfor emplacement on and removal from the upper end of the furnace stackto thereby facilitate any maintenance and repair that may be required.

Another object of the invention is to provide a charging top which,compared to conventional arrangements employing double bells andhoppers, has a simplified and more compact construction, and provides amore uniform distribution of the stock in a furnace.

To'effect these and related ends, the invention contemplates, asindicated generally above, a gastight closure for the upper end of ablast furnace which is in the form of an enclosed hopper for receivingcharging from a skip hoist, and a vertically extending screw conveyorfor feeding the stock from the hopper into the furnace. The stockcharging apparatus of this invention also includes a downwardly inclinedchute for delivering the stock from the skip hoist into the hopper, suchchute being equipped with a gaslock for preventing the escape of blastfurnace gas therethrough. To further minimize the escape of gas, theinterior of the hopper is connected by a conduit with the blast furnaceofftakes so that the pressure of the gas in the hopper is equalized withthe pressure in the furnace to prevent the leakage of gas through thescrew conveyor.

Other objects and advantages of the invention will become apparent fromthe following description.

In the drawings there is shown a preferred embodiment of the invention.In this showing;

FIG. 1 is a vertical sectional view taken in a diametral plane showingthe arrangement and having a stock charging opening at its upper end,and a furnace top of the charging top of this invention on the upper endof a blast furnace;

FIG. 2 is a view similar to FIG. 1 with the charging top removed to moreclearly show the construction of the adapter sleeve which positions andsupports the charging top on a furnace;

FIG. 3 is a sectional view of the hopper shown in FIG. 1 with the supplychute and pressure equalizing conduit disconnected and removedtherefrom;

FIG. 4 is a plan view of the hopper shown in FIG. 3;

FIG. 5 is a vertical sectional view of the stock feed chute shown inFIG. 1 which is used to transfer stock from the skip hoist to thehopper; and

FIG. 6 is a sectional view taken substantially along the line Vl-VIofFIG. 5.

The charging apparatus shown in the drawings comprises a hopper l'which, generally stated, forms a closure for the upper end of a blastfurnace 2. The hopper 1 is supported on the furnace top ring 3 andplatform 4 by an adapter sleeve 5. The top ring 3 and upper edge 6 ofthe top cone 7 define the usual circular opening 8 at the upper end ofthe furnace 2 through which the stock materials are charged therein. Thelower end 9 ofthe cone 7 is supported on the upper end of the furnacestack 10. Openings 11 intermediate the upper and lower ends of the cone7 are connected with gas offtakes 12 for the removal of blast furnacegas from the furnace and its transfer through uptakes and a downcomer(not shown) to gas cleaning apparatus. The adapter sleeve 5 has acylindrical body 13 which extends vertically downwardly from the furnacetop ring 3 and a conical flange 14 at its upper end by which it issupported on the top ring 3.

The hopper 1 has a conically shaped sidewall 15, the lower end 16 ofwhich is supported on the adapter sleeve flange 14. As best shown inFIGS. 1 and 3, a cylindrical sleeve 17 is rigidly connected as bywelding at its upper end to the lower end 16 of the conical side wall15. The upper end of the hopper 1 is closed by a circular plate 18 whichhas a gastight welded connection around its periphery with the upper end19 of the conical sidewall 15. The hopper sleeve 17 is part of a screwconveyor through which stock is fed downwardly by a helical conveyorblade or screw 20. The conveyor screw 20 is rotated by a hollow driveshaft 21 which is rotatably supported at its upper end by a housing 22that forms a gastight closure for an opening 23 in the plate 18 throughwhich the drive for the shaft 21 extends. The drive shaft 21 is drivenby a gear reducing unit 24 and drive motor 25 mounted on the top plateof the housing 22.

When needed, water may be sprayed on the stock in the hopper 1 fromnozzles 26 at spaced intervals along a pipe 27 which extendscircumferentially around the drive shaft 21 at avertical level adjacentthe closure plate 18. Water isfed to the pipe 27 through a supplyconduit 28 connected therewith. A plurality of arms 29 projectingoutwardly from the drive shaft 21 at a point below the pipe 27 operateto stir the stock in the housing 1 and to prevent it bridging the spaceabove the cylindrical sleeve 17 in a manner which would interfere withits downward flow. I

At its upper end the hopper 1 has an opening 30a which is connected withthe lower end of the stock supply chute 30. The chute 30 has arectangular cross section and forms a gastight closure for the'opening300. At its upper end, the chute 30 has a funnel-shaped enlargement 31in which stock, such as iron ore, coke and limestone, is received from askip hoist 32 that travels over a trackway 33. A pair of gates 34 and 35are arranged at spaced intervals along the length of the supply chute 30to control the flow of stock therethrough and prevent the leakage of gasfrom the furnace. The gates 34 and 35 are supported by hinges 36extending transversely of the upper wall 37 of the hopper 30 formovement from their closed positions shown in solid lines to an openposition. The gates 34 and 35 are moved between their opened and closedpositions by fluid pressure motors 38 operating through linkage systems39 that impart a turning movement to cranks 40 on pintle pins that formpart of the hinges 36. The space 41 between the gates 34 and 35functions as a gaslock in which stock is received after having beendeposited in the space 42 above the gate 34 by the skip hoist 32. Thegaslock space 41 is vented to the atmosphere through a pipe 43 under thecontrol of a valve 44, and is pressurized by a pressure equalizingconduit 45 which has a connection 46 at its upper end with the space 41and a connection 47 at its lower end with the interior 48 of thehopper 1. A valve 49 controls the pressurizing action of the conduit 45.

The gate motors 38 and pressurizing valves 44 and 49 are operated in asequential manner, for example, by a suitable control mechanism (notshown), to effect the transfer of stock from the skip hoist 32 into thehopper 1. Prior to movement of the skip 32 to a position in which itscontents are emptied into the space 42, the gate 34 is moved by itsfluid pressure motor 38 to its closed position, and the valve 44 isoperated to vent the space 41 to the atmosphere. After the skip 32discharges its contents into the space 42, the gate 34 is opened torelease the material in the chamber 42 for gravitational movement intothe gaslock chamber 41. The valve 44 is then closed and the gate 34 isreturned to its closed position. The valve 49 is then opened to equalizethe pressure of the gas in the chamber 41 with the pressure of the gasin the hopper 1. The gate 35 is then moved to its open position torelease the material in the chamber 41 for movement into the hopper 1.The valve 49 is then closed and the valve 44 is opened to connect thegaslock chamber 41 with the atmosphere. The parts of the hopper 30 arethen ready to transfer another load of stock from the skip 32 to thehopper 1. Since one of the gates 34 and 35 is always in its closedposition, it will be apparent that the chute 30 and its associated partsare effective to prevent the escape of gas from the hopper l at alltimes.

Although the drawings show only a single chute 30 and skip hoist 32 forsupplying materials thereto, it will be understood that additionalcharging chutes 30 and associated skip hoists may be provided at spacedintervals about the hopper 1. In practice, the hopper 1 will be providedwith at least two, and preferably three, supply chutes 30 at spacedintervals about its periphery in order to supply sufficient stock tosatisfy the requirements ofthe blast furnace 2.

In operation, the hopper 1 is maintained filled with stock to a levelabove the agitating arms 29 but below the spray nozzles 26, and rotationof the screw conveyor by the motor 25 operates to continuously feedmaterial downwardly through the sleeve 17 into the furnace 2. In thismanner, the space about the interior of the cylindrical sleeve 17through which the conveyor blade 20 is rotated will be maintained filledwith stock, and such stock will be effective to prevent the leakage ofsubstantial quantities of gas upwardly into the hopper 1. Any gas thatleaks through the stock in the screw conveyor to the hopper l is removedthrough a pressure equalizing connection 51 that operates to maintainthe pressure in the hopper 1 equal to that in the space 52 above theburden in the furnace and in the gas'offtakes 12. The connection 51comprises an expansion chamber 53 which has a gastight connection withan opening 54 in the plate 18 and is connected by a gas removal duct 55with one of the gas offtakes 12. A fan 56 in the duct 55 removes any gasfrom the expansion chamber 54 that leaks into the hopper 1 and deliversit through the exhaust duct 55 to the offtake 12.

The stock charging apparatus of this invention may be readily assembledon a conventional blast furnace 2 by the first installing the top ring 3on the furnace platform 4, and then lowering the adapter sleeve to aposition with its flange 14 supported on the top ring 3. Next, thehopper l with its screw conveyor is lowered to move the screw conveyorcylinder 17 with a telescoping action downwardly into the adapter sleeve5 to the position shown in FIG. 1. Assembly of the apparatus is thencompleted by connecting the pressure equalizing connection 51 with theopening 54 in the hopper cover plate 18 and the gas uptake 12, and bymounting the stock supply chute 30 in position with its lowerendconnected with the opening 30a in the hopper 1.

In case maintenance and repair of the charging top of this invention isneeded, the construction of the hopper 1 and its mounting on the blastfurnace 2 facilitates its removal and replacement. Removal may beeffected readily by disconnecting and removing the stock supply chute 30and the gas pressure equalizing connection 51. After removal of theseparts, the hopper l and screw conveyor may be removed for repair andreplacement by elevating them to a position above the adapter sleeve 5.

From the foregoing, it will be apparent that the hopper 1 and itsdownwardly extending screw conveyor operate to deliver stockcontinuously to the furnace 2 without the connection of the furnace atany time to the atmosphere. Due to the rotating movement of the screwconveyor blade 20, it will also be apparent that the stock from thehopper 1 is distributed more uniformly about the furnace 1 than ispossible with conventional charging tops employing bells and hoppers,including constructions which are equipped with a third bell androtating hopper. Attention is particularly directed to the fact that thehopper 1 forms a gastight cover for the upper end of the furnace 2 whichconfines the blast furnace gas to the space between the top cone 7 andthe upper surface of the furnace burden in such manner that it isremoved from the space 52 through the gas offtakes 12.

While one embodiment ofmy invention has been shown and described, itwill be apparent that adaptations and modifications thereof may be madewithout departing from the scope ofthe appended claims.

I claim:

1. A charging top for a blast furnace comprising an enclosed hoppermounted on the upper end of said furnace and forming a gastight covertherefore, and stock feeding means comprising a tube opening into saidhopper and extending vertically downwardly therefrom into said furnace,a helical conveyor element mounted for rotationin said tube, and meansfor rotating said conveyor element to feed stock from said hopper andthrough said tube into said furnace, said conveyor element and the stockin said tube operating to restrict the flow ofgas from said furnace intosaid hopper.

2. A blast furnace charging top as defined in claim 1 characterized by adownwardly inclined supply chute having means at its upper end forreceiving blast furnace stock from a charging skip and its lower endopening into said hopper, and gaslock means comprising a pair of valvegates along the length of said chute operable to control thegravitational movement of stock downwardly through said hopper into saidfurnace and to prevent the leakage of blast furnace gas from saidhopper.

3. A blast furnace charging top as defined in claim 1 characterized by agas-bleed conduit connecting the interior of said hopper with the blastfurnace offtakes and operating to maintain the pressure of the gas insaid hopper at the pressure of the gas in the upper end of said furnace.

4. A blast furnace charging top comprising, the combination with the topcone of a blast furnace, gas offtakes connected with said cone at pointsintermediate its upper and lower ends, and a stock charging opening atits upper end, of an enclosed hopper mounted on the upper end of saidcone and forming a gastight cover for said opening, a tube opening intosaid hopper and extending downwardly therefrom through said chargingopening, said tube being concentric with respect to said cone andcharging opening, a conveyor screw mounted for rotation in said tube,and means for rotating said screw to feed stock from said hopperdownwardly through said tube into said furnace.

5. A blast furnace charging top as defined in claim 4 characterized bymeans including a downwardly inclined chute and gaslock for deliveringstock to said hopper.

6. A blast furnace charging top as defined in claim 4 characterized bymeans for equalizing the gas pressures in said hopper and furnacecomprising a pressure equalizing conduit connecting the interior of saidhopper with said blast furnace offtakes.

7. A blast furnace charging top comprising, the combination with the topcone of a blast furnace having a stock charging opening at its upperend, of an enclosed hopper mounted on the upper end 'of said cone andforming a gastight cover for said opening, a tube opening into saidhopper and extending downwardly therefrom through said charging opening,said tube being concentric with respect to said cone and chargingopening, a conveyor screw mounted for rotation in said tube, and meansfor rotatingsaid screw to feed stock from said hopper downwardly throughsaid tube into said furnace.

8. A blast furnace charging top comprising, the combination with the topcone of a blast furnace having a stock charging opening at its upperend, and a furnace top ring mounted concentrically with respect to saidopening, of means forming a gastight enclosure for said openingcomprising a cylindrical adapter sleeve supported on said top ring anddepending therefrom through said charging opening into said furnace, anenclosed hopper having a downwardly extending cylindrical tube receivedin said sleeve with a telescopic fit, a conveyor screw mounted forrotation in said tube, and means for rotating said screw to feed stockfrom said hopper downwardly through said tube into said furnace.

9. In a charging top for a blast furnace having a top cone with acharging opening in its upper end and its lower end supported on thestack of said furnace, the combination comprising an enclosed hoppermounted on the upper end of said cone and forming a gastight cover forsaid charging opening, a tube opening into said hopper and extendingdownwardly therefrom through said charging opening, said tube beingconcentric with respect to said coneand charging opening, a conveyorscrew mounted for rotation in said tube, and means for rotating saidscrew to feed stock from said hopper downwardly through said tube intosaid furnace.

10. A blast furnace charging top as defined in claim 9 characterized bythe upper end of said tube and said charging opening being at the samevertical level.

11. A blast furnace charging top as defined in claim 10 characterizedfurther by said tube having an axial length such that its lower endterminates at a vertical level adjacent the lower end of said top cone.

12. In a charging top for a blast furnace having a top cone with acharging opening in its upper end and its lower end supported on thestack of said furnace, the combination comprising a hopper in the formof a conical shell extending upwardly from the said upper end of saidtop cone. said shell having an opening in its lower end concentricallyarranged with respect to said charging opening and at the same verticallevel, means for feeding stock from said hopper into said furnaceincluding a tube having its upper end connected with said conical shellabout the said opening therein, a conveyor screw mounted for rotation insaid tube, and means for rotating said screw to feed stock from saidconical shell downwardly through said tube into said furnace, said tubehaving an axial length such that material discharged therefrom is fedinto said furnace at a vertical level adjacent the lower end of saidcone, and means including a cover over the upper end of said hopperrendering it effective as a gastight enclosure to prevent the leakage ofblast furnace gas through said top cone charging opening.

13. A blast furnace charging top as defined in claim 12 characterized bymeans for feeding stock to said hopper comprising a downwardly inclinedchute having its lower end opening into said hopper through said conicalshell, means at the upper end of said chute for receiving blast furnacestock from a charging skip, and gas lock means comprising a pair ofvalve gates along the length of said chute for controlling thegravitational movement of stock from said stock receiving means intosaid hopper and for preventing the leakage of blast furnace gas fromsaid hopper.

